I use MQTT pretty heavily in HA, with a mixture of esphome, tasmota, home brew arduino stuff, and some very custom integrations.
Ive been holding off on enabling mqtt autodiscovery because i havent wanted all my devices (particularly the esphome and tasmota ones) to get duplicated – and ive been onboard since before that was a thing.
So - if i enable auto discovery, what happens to the already configured devices ? Is it smart enough to know that a switch/light/sensor is already configured for that state/command topic ?
Are any/all of your devices compatible with auto-discovery? They need to post their own config to a special topic for any of that to work. If you use a client to view that topic, you should be able to see the posts.
One safe method would be to temporarily remove all of your manually configured mqtt devices, enable auto-discovery, restart, see what shows up.
I guess the bigger question is why. If you e already got the manual config installed and working, what’s the point.
Turn on autodiscovery, set homeassistant: true in the zigbee2mqtt configuration.yaml and let these be autodiscovered. As long as you don’t type setoption19 1 in tasmota, or the equivelant in esphome, nothing will happen with your existing topics.
Do you know what will happen to the existing z2m entries ? Will they get duped ?
Its not a HUGE deal if i have to cleanup, but would be a non trivial amount of work.
I think they might get duped with “_2” added to end… But since you can now rename entity_ids for most things, you should be able to adjust once you notice the duplicates.